I saw another dock like this floating around, but wasn't happy with the design, so I made my own one. The hooks are stronger, and require a set of steps to attach (See below). This is to make certain the dock and adapter sit snugly and won't come apart if the dock is tipped.
Important: In order to get the tabs to lock onto the side, do not try to simply force the tabs on. Instead:
Keep the Gamecube dock adapter portion flat as pictured.
Face the Switch dock down, so the front face is facing the ground and the slot where the Switch goes into is facing you.
Slide the Switch dock in from the back, sliding the hooks through the slot the Switch goes into until you reach the bottom of the slot.
Slowly turn the Switch dock upright.
There are no slots/grooves for the face-plate and buttons, as the print orientation would go to hell if there were, just line them up where you want them, and glue those suckers on.
The Gamecube controller racks were designed by Larsenv, and can be found here:
.25mm for the dock itself, .15mm for everything else
3 Layers for the top and bottom works well.
Don't have to worry about speed too much, as the design is easy for most printers to print at speeds, I printed the pictured dock at 1.7x my optimal speed with little to no stringing or artifacting.